Caffeine is a natural product belonging to the alkaloid class. It was reputed to have first been consumed by a Chinese emperor, Shen Nueg, in about 2700 B.C, but it actually has been consumed since the stone age. Caffeine was actually first discovered and isolated by German chemist Friedrich Runge. The structure of the molecule was discovered by Hermann Fischer. Since its discovery, caffeine has certainly not declined in use, but it is acknowledged by health officials as dangerous in large amounts.
This drug is found mainly in coffee, tea, some sodas, and energy drinks. It is a psychoactive stimulant drug in humans and other animals, where it wards of drowsiness, and maintains alertness in the human body. It is very commonly found in the beans, leaves, and fruit of over 60 different species of plant, and as a result it is the world's most widely consumed drug. Tea leaves contain about 2%-5% caffeine.Caffeine is a white crystal xanthine alkoloid molecule. It works as a stimulant by interfering with the receptors in the brain. In this experiment, the purpose is to extract the caffeine from tea. In this reaction, we decaffeinated tea in order to obtain the caffeine. In this method, we used dichloromethane as a solvent in order to absorb the caffeine and separate it from the water so that the caffeine could be extracted later. Dichloromethane is used because it much less dangerous than other solvents, as it doesn't cause brain or respiratory damage.
Procedure
To start the experiment, we filled a 500 ml Erlenmeyer flask with 125 ml of water. Then we emptied several bags of Lipton tea and measured out 12.5 grams of the contents. Then we measured out 12.5 grams of CaCO3. Then we added the tea and CaCO3 to the water and boiled and stirred the mixture for 20 minutes.
Once the boiling was done, we used the vacuum filter and buchner funnel to separate the tea particles from the rest of the mixture. Then we transferred the filtrate to another clean 250 ml Erlenmeyer flask and added 100 ml of dichloromethane. After swirling the mixture for ten minutes, we used a separatory funnel to separate the dichloromethane from the water. We had to constantly swirl the mixture and occasionally add more dichloromethane to make the separation layers between the water and the dichloromethane more distinct. The purpose of this was to make the separation easier.
Once we had the dichloromethane separated from the layer of water in the separatory funnel, we had to use a few grams of anhydrous Na2SO4 to absorb any additional water molecules that may have still been mixed with the dichloromethane. After adding the Na2SO4, we decanted the dichloromethane solution into a round bottom flask, and used a rotary evaporator to separate the dichloromethane from the caffeine. Then we collected our yield, and weighed it. Finally, we recorded our data and cleaned up.
Results
We had a fairly decent yield of caffeine at the end of the experiment. The mass of our final sample was .12 grams. The color of our sample was greenish white, and it had the texture of a cake. It was very similar in texture to solid trimyristin. It is highly likely that our sample of caffeine was impure. The reasons for this include the different colors in the sample as well as the odor of the sample, which smelled like tea. It is possible that some of the substances that were in the Lipton teabags got mixed in with the caffeine, rendering it impure.
Conclusions
Although we had a substantial yield of caffeine from tea, different sources of error may have prevented a completely pure sample of caffeine from being produced. Unclean beakers and other lab equipment covered with chemicals from previous experiments may have contaminated our final substance. The original procedure called for chloroform, but we used a similar chemical, methylene chloride, due to safety reasons. This may have altered the end results as well. These errors most likely caused changes in our end result.
For further experiments, it is possible that one could figure out best ways to purify the caffeine, as our caffeine product was not pure.
References
Techniques and Experiments for Organic Chemistry (Fith Edition) by Addison Ault pg. 326
Table of Contents
Extraction of Caffeine From Tea
Ellis R., Khaliah M., Ali
Introduction
Caffeine is a natural product belonging to the alkaloid class. It was reputed to have first been consumed by a Chinese emperor, Shen Nueg, in about 2700 B.C, but it actually has been consumed since the stone age. Caffeine was actually first discovered and isolated by German chemist Friedrich Runge. The structure of the molecule was discovered by Hermann Fischer. Since its discovery, caffeine has certainly not declined in use, but it is acknowledged by health officials as dangerous in large amounts.
This drug is found mainly in coffee, tea, some sodas, and energy drinks. It is a psychoactive stimulant drug in humans and other animals, where it wards of drowsiness, and maintains alertness in the human body. It is very commonly found in the beans, leaves, and fruit of over 60 different species of plant, and as a result it is the world's most widely consumed drug. Tea leaves contain about 2%-5% caffeine. Caffeine is a white crystal xanthine alkoloid molecule. It works as a stimulant by interfering with the receptors in the brain. In this experiment, the purpose is to extract the caffeine from tea. In this reaction, we decaffeinated tea in order to obtain the caffeine. In this method, we used dichloromethane as a solvent in order to absorb the caffeine and separate it from the water so that the caffeine could be extracted later. Dichloromethane is used because it much less dangerous than other solvents, as it doesn't cause brain or respiratory damage.
Procedure
To start the experiment, we filled a 500 ml Erlenmeyer flask with 125 ml of water. Then we emptied several bags of Lipton tea and measured out 12.5 grams of the contents. Then we measured out 12.5 grams of CaCO3. Then we added the tea and CaCO3 to the water and boiled and stirred the mixture for 20 minutes.Once the boiling was done, we used the vacuum filter and buchner funnel to separate the tea particles from the rest of the mixture. Then we transferred the filtrate to another clean 250 ml Erlenmeyer flask and added 100 ml of dichloromethane. After swirling the mixture for ten minutes, we used a separatory funnel to separate the dichloromethane from the water. We had to constantly swirl the mixture and occasionally add more dichloromethane to make the separation layers between the water and the dichloromethane more distinct. The purpose of this was to make the separation easier.
Once we had the dichloromethane separated from the layer of water in the separatory funnel, we had to use a few grams of anhydrous Na2SO4 to absorb any additional water molecules that may have still been mixed with the dichloromethane. After adding the Na2SO4, we decanted the dichloromethane solution into a round bottom flask, and used a rotary evaporator to separate the dichloromethane from the caffeine. Then we collected our yield, and weighed it. Finally, we recorded our data and cleaned up.
Results
We had a fairly decent yield of caffeine at the end of the experiment. The mass of our final sample was .12 grams. The color of our sample was greenish white, and it had the texture of a cake. It was very similar in texture to solid trimyristin. It is highly likely that our sample of caffeine was impure. The reasons for this include the different colors in the sample as well as the odor of the sample, which smelled like tea. It is possible that some of the substances that were in the Lipton teabags got mixed in with the caffeine, rendering it impure.
Conclusions
Although we had a substantial yield of caffeine from tea, different sources of error may have prevented a completely pure sample of caffeine from being produced. Unclean beakers and other lab equipment covered with chemicals from previous experiments may have contaminated our final substance. The original procedure called for chloroform, but we used a similar chemical, methylene chloride, due to safety reasons. This may have altered the end results as well. These errors most likely caused changes in our end result.
For further experiments, it is possible that one could figure out best ways to purify the caffeine, as our caffeine product was not pure.
References
Techniques and Experiments for Organic Chemistry (Fith Edition) by Addison Ault pg. 326